Electric furnace.



EATENTED JULY 2, l907.

.Not 858,718.

1T? ILE;

bm I

UNrrnn STATES PATE NT OFFICE.

PAUL LOUIS TOUSSAINT HEROULT, OF LA PRAZ, FRANC-E, ASSIGNOR TO SOCIETE ELECTRO- METALLURGIQUE FRANCAISE ELECTRIC Application filed April 18 To all whom it may concern:

Be it known that l, PAUL Louis TOUSSAINT lili:- ROULT, a citizen ol the Republic of France, residing at La Praz, Savoie, France, have invented certain new and useful .improvements in Electric Furnaces, of which the following is a specification.

This invention aims to provide certain improve- `ments in electric iurnaces, whereby the power factor (when an alternating current is used) is increased, and

l() whereby the resistance to the passage of the current is lessened, and also whereby certain other advantages are obtained hereinafter referred to in detail,

The accompanying drawings illustrate an embodi ment of the invention.

Figure l is a vertical section of a furnace; Fig. 2 is a horizontal section thereof; Fig. 3 is a sectional view of a detail on an enlarged scale.

Referring to the embodiment illustrated, the body A of the furnace may be o carbon as usual, bound by a surrounding jacket or rings of iron, steel or the like.

The current passes from the electrode B through the charge, and thence through the cast iron base to cables D. Ordinarily the jacket is made of iron or steel forming a continuous ring of magnetic material, forming an uninterrupted medium for the lines of force around the direct line oi thel current, and introducing a considerable impedance into the circuit. l propose to eliminate this impedance by breaking the circuit. Forthis purpose the iron portion E of the jacket is not continuous around the carbon body o the furnace, but is broken at one or more points, the edges being connected by a strip Fof copper or other non-magnetic material connected to the viron in any suitable Way, as by means offrivets G. The jacket may be arranged 'as shown to A run continuously from the top to the bottom, in which case the copper Willbe similarly arranged, or the iron and also the copper may be arranged in variety ol other ways to bind the body of the furnace together, and at the same time to avoid the provision of a com- 4() plete circuit of magnetic material. The impedance may be so reduced by this construction as to increase the power factor from GO as in the ordinary alternating current furnaces to 92 or S3.

A more perfect contact than usual between the body y of the furnace and the cast iron base is secured by prt vidng long and preferably forked pins H, which extend from the base upward int'o the carbon block, and the lower ends of which are cast into the base plate C so as tp make perfect Contact therewith. This construction increases by about two per cent. or more the conduc-y Specification of Letters Patent.

, OF FROGES, TSRE, FRANCE.

Fermana.

Patented July 2, 1907.

:1906. Serial llo. 312,318.

tivity as compared With previous constructions, and is at the same time vcry cheap and very readily applied to the furnace.

For making a good connection between the cable or cables D and the plate C, I provide a special Contact block .l of copper about which the plate C is cast so as to effect au intimate, welded, union. Practically an alloy is formed tapering off to copper on one side and iron on the other. To secure this union the parts may be specially' heated. es by means of thermit or the electric arc. The blot-1l I is preferably plated at least on the .laces which come into contact with the cast iron, with tin or other metal which keeps the copper perfectly clean and unoxidizcd and which melts at the Casting` temperature, and thus insures a clean Contact between the cast iron and the copper. A cable block L which may be ol' the usual type, of aluminium cast upon the ends of the cables, is clamped strongly upon the contact block J, as for example by means of a bolt M, the contact faces ol the blocks I and L being planed to insure a goed contact. This method of connecting the cable to the base plate effects a material increase in conductivity, as compared with the connecting oi the cable block directly to the cast iron plate. The complete furnace, therefore, has a very limitd ldss of current '75 through resistance and a v-ery high power factor, Whereby considerable economies in cost of operation and also"I in the cost of installation are effected.

Though l have described with great particularity of detail a certain specic embodiment of the invention, S0 yet it is not to be understood therefrom that the invention is limited to the exact embodiment described. Various modifications thereof in detail and in the arrangement and combination of the parts, maybe made by those skilled in the art, without departure from the invention.

What claim isz- 1. An electric furnace having a body`A of carbon, land a jacket surrounding the sume comprising a portion E ot iron, said portion being divided und its ends connected by n portion F of copper to break the lines of force around the furnace` 2. An electric furnace having a base plate serving al a current terminal and made of cast iron with rods of wroughtv iron projecting luto the body of the furnace and hav-lng their lower ends cast luto the base plate.

In witness whereof, I have hereunto signed my name 1n the presence of two subscribing witnesses,

PAUL Louis ToUssAinT Hnnouur.

Witnesses:

D. ANTHONY Umm, Firm Wm'rl. 

